Discovery of Cepheid Stars
A relationship between the period and luminosity for classical Cepheids is discovered in 1908 by Henrietta Swan Leavitt in an investigation of thousands of variable stars in the Magellanic Clouds
Astronomer profile · World History Database
Henrietta Swan Leavitt
Henrietta Swan Leavitt discovered the relationship between the period and intrinsic brightness of Cepheid variable stars while studying photographic plates at Harvard College Observatory.
Why Henrietta Swan Leavitt matters in astronomy
The period–luminosity relation turned Cepheids into distance indicators. It became a key step in measuring the scale of the universe and in the later work that established the existence of galaxies beyond the Milky Way.
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Leavitt, Henrietta SwanName2, Name1 format
Henrietta Swan Leavitt timeline in the database
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Sources and editorial provenance
Compiled and edited by World History Database
Historical chronology compiled from the World History Database and checked against major scientific and historical reference sources.
Last reviewed: September 2026.
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